ABSTRACT
Objective To study the value of 99Tcm-DTPA dynamic renography in evaluating the function of duplex kidneys in pediatric patients.Methods Twenty-five pediatric patients with duplex kidneys diagnosed by ultrasound or MR urography (MRU) were included (9 males,16 females; mean age:(23.80 ± 20.97) months,range:2-72 months).Twenty patients (9 males,11 females; mean age:(32.95 ± 23.58) months,range:2-72 months) with urinary tract infection but without duplex kidneys confirmed by ultrasound or MRU were chosen as control group during the same period of this study.All patients and controls were divided into two subgroups according to their ages (group Ⅰ,0-24 months; group Ⅱ,25-72 months).The research was approved by the ethics committee,and all patients' parents (or guardians) signed informed consents.The time-activity curve was generated on the dynamic imaging data automatically with GFR calculated.The uptake rates of the upper and lower moieties were measured by drawing the corresponding ROIs in the duplex kidney.Dunnett-t test was used for statistical analysis.Results There were 25 patients with 26 duplex kidneys (1 case bilateral),16 on the left and 10 on the right.The time-activity curve of 6 cases was normal,9 with continuously upward type,4 with high level plateau type,2 with parabolic type and 5 with low level plateau type.There were 19 abnormal kidneys in group Ⅰ and 7 in group Ⅱ,and 20 kidneys in each control subgroup.The GFR of patients with normal renography was (78.81 ± 15.97) ml/min (group Ⅰ) and (64.68 ± 11.15) ml/min (group Ⅱ),continuously upward type was (72.11 ±22.76) ml/min (group Ⅰ) and (63.41 ± 16.42) ml/min (group Ⅱ),high level plateau and parabolic types were (68.74 ± 16.17) ml/min and (65.26 ± 15.27) ml/min in group Ⅰ,respectively.There was no statistically significant difference between the GFR of different renography type groups and that of the controls (group Ⅰ:(79.35 ±13.31) ml/min,group Ⅱ (76.46 ±9.69) ml/min;all P ＞0.05).The GFR of patients with low level plateau type was (45.83 ± 10.17) ml/min (group Ⅰ) and (45.53 ± 10.42) ml/min (group Ⅱ).There was statistically significant difference between the GFR of two subgroups of low level plateau type and that of control group,respectively (both P ＜ 0.05).Among the 26 abnormal kidneys,23 could be separated into upper and lower moieties.Among the 23 duplex kidneys,15 cases had uptake rate less than 10％ of that of the whole kidney,5 cases ranging from 10％ to 30％,and 3 cases greater than 30％.Conclusions Quantitative evaluation of duplex kidney functions can be performed with 99Tcm-DTPA renography.It may provide important information for the management of pediatric patients with duplex kidneys.